I am not familiar with CA laws but NY is very stringent so the price sounds about right for the type of job you're doing.

County is usually closer to accurate, but really the only way to get the accurate size is to go measure it yourself.

@Harrison CookYour post kindles lots of questions.In the "good old-days" most heating systems were vastly oversized for the building they were heating - energy was relatively cheap, insulation was non-existant to poor ... so it was easier and safer to {drastically} oversize.Today, while energy {in North America}  is still relatively cheap for the moment,  we have a much better understanding of how to make buildings more efficient {though you might not think so looking at the construction industry in the U.S.A. and Canada}  and there are often more cost-effective measures than simply replacing an old, over-sized heating plant with a new, over-sized heating plant.You really need to - or at lease should -  perform a heat load analysis to properly size your heating system, a component of which, is determining the rate of heat loss of the building envelope.  

When this is measured and compared accordingly this can be become a six figure matter of difference.  

The limit is actually 10, but the financing qualifications are more stringent and terms are worse after 4.

Occupancy is not a particularly valid measure.

He could survey a vacant lot where the proposed plant was to be built and using a slide ruler with a tape measure he could pinpoint within an inch the exact same location the licensed surveyors marked using their transits.  

@Austin Petrie Great question and I agree that MIRR is, generally speaking, a more useful measure than IRR. 

@Hadar Orkibi and @Aaron Klatt, what is a good measure to use for growth in an area?

I agree with @Chris Sellers that your next step is to begin narrowing down your market choices.My best advice:Be ruthless with the numbers - Be crystal clear on your financial objectives and how you'll measure success.